feat(subtitles): add local Japanese subtitle generation

- Generate Japanese SRTs through the overlay modal or launcher
- Support managed whisper.cpp models and optional dialogue detection

src/config/definitions.ts

@@ -1,4 +1,5 @@
 import { RawConfig, ResolvedConfig } from '../types/config';
+import { DEFAULT_SUBTITLE_GENERATION_CONFIG } from '../shared/subtitle-generation';
 import { CORE_DEFAULT_CONFIG } from './definitions/defaults-core';
 import { IMMERSION_DEFAULT_CONFIG } from './definitions/defaults-immersion';
 import { INTEGRATIONS_DEFAULT_CONFIG } from './definitions/defaults-integrations';
@@ -54,6 +55,7 @@ const { immersionTracking } = IMMERSION_DEFAULT_CONFIG;
 const { stats } = STATS_DEFAULT_CONFIG;
 
 export const DEFAULT_CONFIG: ResolvedConfig = {
+  subtitleGeneration: { ...DEFAULT_SUBTITLE_GENERATION_CONFIG },
   subtitlePosition,
   keybindings,
   websocket,